FUNDUS TO ANTRUM RATIO MEASURED WITHIN ONE WEEK AFTER ENDOSCOPIC SLEEVE GASTROPLASTY PREDICTS TOTAL BODY WEIGHT LOSS OVER TIME
Kaveh Hajifathalian*, Donevan R. Westerveld, Andrea S. Kierans, Amit Mehta, Angela Wong, Grace C. Lo, Sarah Oh, Reem Z. Sharaiha
Gastroenterology and Hepatology, New York Presbyterian-Cornell, New York, NY
To characterize the upper GI fluoroscopic (UGI) findings after endoscopic sleeve gastroplasty (ESG) and assess predictors of greater percent total body weight loss (%TBWL).
The immediate post-procedural (1-7 days post-ESG) examinations of 162 patients between 2015-2018 were retrospectively evaluated by 2 blinded radiologists and were correlated with % TBWL during follow up. Multilevel mixed-effects logistic regression was used to build a model in half of patients (random subset) for predicting the probability of achieving a TBWL of 5% or more over time using fluoroscopic measurements as the main predictor variable in addition to baseline body mass index and their compliance with follow up visits, while allowing for variation in weight loss between study participants. The model was subsequently validated using the remaining half of the cohort (i.e. validation sample).
None of the patients had contrast extravasation or leak on immediate or follow-up UGI after ESG. The mean post-procedural UGI gastric fundus/antrum transverse measurement ratio was 1.2'±0.62, and fundus/body ratio was 3.3'±1.1. Higher fundus/antrum ratio was significantly associated with probability of achieving %TBWL of 5% or more in multivariable analysis (OR=2.5, 95%CI 1.5-4.2, p=0.001). Fundus/body ratio was not a significant predictor of %TBWL. Sensitivity multivariable analysis, revealed that fundus/antrum ratio remains a significant predictor of achieving %TBWL of 10% or more, and 15% or more as well (OR=2.1, p=0.003; and OR=1.7, p=0.041, respectively). In discriminant analysis, fundus/antrum ratio had an area under the ROC curve of AUC=0.79 (95%CI 0.77-0.81) for predicting %TBWL>=5% (Figure 1). Fundus/antrum ratio of >=0.47 had a 63% sensitivity and 78% specificity, and positive likelihood-ratio of 2.8 to predict TBWL>=5%, and classified 72% of the %TBWL outcomes correctly. A prediction model was built in a random subset of 81 patients for predicting the probability of achieving a TBWL of 5% or more, using fundus/antrum ratio, baseline BMI, time since ESG, and compliance with follow up visits. The model was validated in the remaining half of the cohort showing excellent discrimination (AUC=0.88, 95%CI 0.85-0.91), and excellent calibration with close agreement between observed and predicted probabilities of achieving TBWL of 5% or more (Figure 2).
A simple fluoroscopic score of stomach fundus/antrum ratio measured immediately after ESG was found to be a significant predictor of %TBWL during follow up. A large fundus to antrum ratio can potentially lead to lower levels of Ghrelin and better early satiety and delayed gastric emptying leading to better weight loss. Given the higher risk of tissue apposition in the fundus, these results are important in the improvement ESG technique with emphasis on better apposition in the distal body and antrum to achieve better weight loss.
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